Removing only numbers but keep the words like "3D" in R?

Question

I have been coding text mining with R recently,but I have trouble dealing with data preprocessing. I have a string like this below:

"I want to buy 3D printer, but it costs 3000 dollars."

I want keep words "3D" but remove "3000", it should be like this below:

"I want to buy 3D printer, but it costs dollars."

I use corpus <- tm_map(corpus, removeNumbers) but this will remove all the numbers in the text, so I will have the term "D printer" in the result but it should be "3D printer".

Is there any possible way to fix this probelm? Thanks!

Answer 1

We can use sub

gsub('3\\d+\\s', '', str1)

If this needs to be general,

gsub('\\b\\d+\\s', '', str1)
#[1] "I want to buy 3D printer, but it costs dollars."